1. Field of the Invention
The present invention relates generally to a heat sink structure and a manufacturing method thereof, and more particularly to an annular heat sink structure and a manufacturing method thereof.
2. Description of the Related Art
The conventional cylindrical heat sink includes a cylindrical body and multiple radiating fins connected to the circumference of the cylindrical body. There are several conventional measures for connecting the radiating fins to the circumference of the cylindrical body. For example, a prior art discloses a cylindrical heat sink and a method of tightly planting radiating fins of the heat sink and an application device thereof. According to the method, a mold seat drivable by a power source to create stepped rotational operation is provided. A cylindrical body is located on the mold seat. The circumference of the cylindrical body is formed with multiple channels. A radiating fin assembly is provided. The radiating fin assembly includes multiple radiating fins arranged on a lateral side of the mold seat. The cylindrical body intermittently rotates to drive and align the channels with the radiating fins. A radiating fin insertion device is used to push the radiating fins and sequentially insert and locate the radiating fins into the channels of the cylindrical body. After the radiating fins are fully inserted in the channels of the cylindrical body, a successive tightening process is performed to tightly integrally connect the radiating fins to the channels. Accordingly, the radiating fins are located on the circumference of the cylindrical body to form a heat sink.
Another prior art discloses a tightening method for a heat sink. The heat sink includes a heat conduction base seat and a radiating fin assembly. One surface of the base seat is formed with multiple channels and guide grooves positioned between two channels. The radiating fin assembly includes multiple radiating fins. A mold having an internal space and a press end section is provided. A tightening/connection process is performed to press and insert the heat sink into the internal space of the mold. The press end section is axially thrust into the guide grooves to compress and deform the channels. At this time, the radiating fins are pressed to tightly integrally connect with the deformed channels. The above method is better than the pressing and riveting method of the conventional heat sink. The breakage of the puncher or blade mold can be effectively reduced to promote the ratio of good products. Also, the precision and quality of the products are increased. This method is conveniently applicable to various heat sinks to form different types or shapes of heat sinks.
In both the above methods, the radiating fin is first inserted into a channel and then a mold is used to press the guide grooves on two sides of the channel to deform the channel and press the radiating fin to tightly integrally connect the radiating fin with the deformed channel. Such process has some problems as follows:    1. The outer surface of the cylindrical body not only is formed with the channels, but also is formed with the guide grooves. The channels and the guide grooves are alternately arranged. That is, the number of the channels per unit surface area is reduced. As a result, the number of the mounted radiating fins is reduced.    2. The manufacturing method includes numerous steps so that the manufacturing time is quite long.